A number of technologies are used to manufacture non-metallic structural components capable of sustaining significant loads. Typically these involve composite materials that combine a resin with some type of fiber reinforcement. Advanced composites have been developed that use expensive, high-performance resins and fiber reinforcement with properties of high strength and stiffness. The design and manufacturing of advanced composites usually employ very complicated processes and machinery that involve saturating the fiber with the resin, then causing the resin to bind, typically in a mold apparatus. For most manufacturing processes, thermoset resins, and increasingly thermoplastic resins, require immense hand labor to fabricate, multiple repetitive processes, and often autoclave (pressure vessel) curing. This is an expensive and time consuming process, with little room for error.
One technique for manufacturing advanced composites is referred to as Laminated Object Manufacturing (LOM). This technology applies a full “ply” of material, with some sort of integral adhesive onto a tool-less platen, and cuts the ply (by laser, knife, etc.) to the final shape. Repeating this process several times eventually results in the buildup of enough thickness to contain the finished part. During lamination, unwanted areas are scored in a square/rectangular pattern, and after lamination the part is “de-cubed” to remove the unwanted areas from the monolithic block, revealing the finished part. This technique only allows for entire plies to be placed, and not individual fibers, and generates a large amount of waste material in the “cubing/de-cubing” process. In addition, any given ply will have only one fiber orientation.
Fiber/tow placement is a technique wherein an individual fiber, or tow, pre-impregnated with resin is placed in, or on, a tool or mold that contains the basic shape, and this process usually employs thermoset materials. It is somewhat akin to a mechanized version of hand layup.
Filament winding is similar to fiber placement, except that this process is more amenable to cylindrical shaped objects (not just circular cylinders, but any cross section cylinder.) As in fiber placement, a tool (mold) is required, and the process is typically employed with thermoset materials.
Recently, 3D printing devices have become widely used, to the point of being available as affordable desktop models for the average hobbyist. Their utility is also clear beyond being a novelty, as they are used to create medical prostheses, dental implants, master models for lost-wax casting processes, and a host of other useful embodiments. However, all of these 3D printed items lack one important attribute, the ability to be used as structural components with significant loads beyond simple low compressive loading. In order to be used as viable structural components the some form of long-fiber reinforcement needs to be introduced using, for example, one of the techniques described above.
Fiber Reinforced Advanced Composites are ubiquitous throughout our present day experiences, in automobiles, aircraft, and increasingly in civil structures. But, these advanced composites typically come with a large price tag (due in part to increased material, design, and manufacturing costs) that is significantly beyond that of the metallic structures they replace. Manufacturing decisions must determine whether the increased performance provided by fiber reinforced advanced composites justifies the increased cost. In addition, there is a middle ground where high performance composites are not required but a medium-duty fiber reinforced 3D printed part would be useful. These parts could be made from a variety of thermoplastic materials, along with a variety of fiber materials (different base material, woven or not, etc.).
The manufacturing cost of fiber reinforced advanced composites would be significantly reduced by the 3D printing process, eliminating much of the tooling needed for conventional parts, and most of the processing needed for conventional advanced composites.
Thus, a need exists for a device and method for producing long-fiber reinforced 3D printed components that eliminates most, if not all, of the hand labor and tooling, and can offer improved dimensional accuracy on fiber location with reduced cost. There is a further need for a device and method where the 3D printed part can have fibers oriented any desired direction within each individual layer.